As recently as July, oil traded at over $100 a barrel. By January, it had plunged below $50.

Saudi officials have repeatedly blamed supply and demand for the price meltdown. They say they were caught off guard by the price decline, and acknowledge this is putting a lot of pressure on U.S. shale.

"Although Saudi Arabia and OPEC countries did not engineer the reduction in the price of oil, there's a positive side effect, whereby at a certain price, we will see how many shale oil production companies run out of business," Prince Alwaleed bin Talal, a member of the Saudi royal family and prominent global investor, said in January.

The oil games: While the price of oil started falling at the end of the summer, it was exacerbated on Thanksgiving Day when OPEC, led by Saudi Arabia, voted not to scale back on production. That send oil prices diving.

Fisher also noted that the Saudis benefit not just economically, but politically from the oil price decline. Low oil prices especially hurt their biggest regional rival: Iran.

"I'm sure King Abdullah thought to himself, 'I've also done a favor vis-a-vis Iran,'" Fisher told reporters. Iran's economy needs oil to trade around $135. Saudi has far larger cash reserves and is thus able to withstand a downturn in prices for much longer.